Targeted microbubbles in promoting angiogenesis and changes of myocardial mechanics after stem cell transplantation in rabbit models of acute myocardial infarction

Objective To assess the efficacy of bone marrow mesenchymal stem cells(BMSCs) being transplanted into rabbit models of acute myocardial infarction(AMI) after injected targeted microbubbles by two-dimensional ultrasound speckle-tracking imaging(STI).Methods CD34-targeted microbubbles were prepared.Thirty-six healthy rabbits were randomly and equally divided into three groups,i.e.control group(simply transplant group),common microbubbles group(Transplant +C) and CD34-targeted microbubbles group(Transplant +T).Then myocardial perfusion parameters of pre-and 3 days post-ligation and 4 weeks after stem cell transplantation were compared.Two-dimensional strain images were acquired from left ventricular(LV) short-axis view(at the levels of mitral annulus,muscle papillary and apex),and radial strain rate(SrR),circumference strain rate(SrC),rotation rate(RotR) and rotation(Rot) of three levels in short-axis views were measured by STI.Microvessel density was assessed at last.Results Compared to before stem cell transplantion,A,β and A×β values of Transplant+C and Transplant+T group increased,especially in transplant+T group(all P0.05).SrR,SrC,RotR and Rot of left ventricular anterior regional myocardial function of three levels in short-axis views increased(all P0.01) than before transplantation,and showed correlation with left ventricular eject fraction.Conclusion Targeted microbubbles probably have certain value for angiogenesis after stem cell transplantation.